Rheostat



E. M. BENTLEY.

RHEQSTM.l APPLSCATION FILED MAY 9. ISIS.

Patnted Aug. 19, 1919.

3 SHEETS-SHEET 2 H ifa--- E. M. BENTLEY.

RHEOSTAT.

APPLlcAnoN FILED aus. 1919.

1,313,853. Patented Aug. l19, 1919.

3 SHEETS-SHEET 3.

gnnumlzm Inveniar EDWARD M. BENTLEY, OF LAWRENCE, NEW YORK.

BHEO'STAT.

Specification of Letters Patent.

Patented Aug. 19, 1919.

Application tiled May 9, 1919. Serial No. 295,946.

To all 'whom t may concern.'

Be it known that I, EDWARD M. BENTLEY, a citizen of the United States, residing at Lawrence, county of Nassau, and State of New York, have invented certain new and useful Improvements in Rheostats, the following bem a full, clear, and exact disclosure of t e one form of my invention which I at present deem preferable.

For a detailed description of the reesent form of my invention, reference may had to the following specification and to the accompanying drawings, which illustrate my invention, wherein- Figure 1 is a plan,

Figs. 2 and 3 side elevations, and

Fig` 4 an end elevation of an elementary form of my invention;

Figs. 5, 6 and 7 show a form particularly designed for automatic operation;

Flgs. 8 to 12 show modifications thereof.

My invention relates to a rheostat of the exposed type with a metallic conductor formed in a seriesof loops and means for progressively bringing into electrical connection the opposite sides of each loop to give a variable effective length and resistance thereto.

Referring to Figs. 1 5, A represents a metallic ribbon of suitable resisting material which is extended in a series of loops be tween the bar B near one end of the base E and a bar D near the opposite end. The extremities of the loops are, at the bar D, brought together and secured in a groove in the bar. At the o posite ends the loops are passed around a at bar B which is pulled I y the sprin s C C t0 ut the loops under tension. W ere each oop passes around bar B, it is folded over, as appears in F ig.

4 and started back in anew osition to form the next succeeding loop. n. this way 'the opposite sides of each loop 11e face to face through their entire length and at a sllght distance apart at one end though in contact at the opposite end. Extending across beneath the series of loops is a slide 1n the form of roller or bar F mounted on a traveler G which isfree to slide longitudinally along the strips, being guided by a groove in the base.` As appears in Fig. 3, which shows the slide at the extreme right hand end of its range, the roller F presses slightl upward against the overlying loo s, v ut since'it is at the tip of the loops, it ees not affect the total reslstance of the looped ribbons. But, when the roller F reaches the opposite end of its route, as shown in Fig. 2, it has pressed the opposite sides of the loop into contact and thereby short circuited all of the loops, reducing their total resistance correspondin ly. Between these two extreme positions oroller F are an infinite number of intermediate positions at each of which a greater or less portion of the loops is thus short circuited. Outside of those portions of the ribbon which are thus brought into contact, the ribbon itself may be electro-plated, with copper to eliminate resistance and heating at such points. By this means the ribbon will be entirely short circuited when the traveler G is 1n the position shown in Fig. 2.

In Fi 5 several sets of such loops as appear in ig. 1 are employed and the progressive closing u of the loops is effected y means of a roc er H which has a curved surface of long radius ressing against the loops of each set. In ig. 6 the rocker is turned to open the loops, the tip of each loo bein roc er an the rocker pivoted on an axis h. As shown in Fig. 7 the rocker is formed of a sheet of insulation with metal edge plates h2 by which it is mounted. In Fig. 8 the rocker H is curved on both faces so that it may serve to open and close two sets of loops. In Fig. 9 the ribbons are made tapering toward the closed end or tip to pro vide greater current-carrying capacity as the resistance is decreased. The pendant rocker arrangement of Figs. 5-9 manifestly aii'ords a wide variation of resistance for a small range of movement, requiring a small amount of force to execute. Therefore the arrangement lends itself to operation by a magnet as at K for re lative purposes. It will also be observed t at the rocker H forms a presser for progressively bringing the two conductors upon which it acts into electrical connection, the same being true of the roller F of Figs. 1, 2 and 3. In the rocker form of prser a reat ad vanta e lies in the lon radius o the are in which the face of t e rocker is curved and the extremely short radius on which it is pivoted. By this means a considerable swing of the rocker involves but a sllght longitudinal movement of the flexible ribbon as it is wra pcd and unwrapped on the face of the roc er. while a short range of movement serves to open and close a long attached to one edge of the l loop. Many rheostats require a long len h of resisting conductor, and I am able, y this arrangement, to bring such a long lenth of conductor into a small compass, an by a very limited ran e of mechanical movement, requiring very ittle power, introduce or withdraw the resistance into or from the circuit without arcing or rupture of contact and b infinitesimal degrees.

In Figs. 8 an 9 I have shown as heretofore stated, a two-faced rocker, by which its capacity is doubled. The two sets of loops have their tips secured to opposite ends of the rocker respectively and the flexible conductors of one set draw on the rocker in a direction opposite to Ithe draft of the other Set. Thus the same to-and-from movement of the rocker will either open or close both loops'sirnultaneously, the pull on the pivot of the rocker being neutralized.

In Fig. 10 I have shown means for operating in successions two of the ca rds shown in Fig. 8, the term card meaning a rocker with its applied resistance strips, and the two cards in this ligure being marked respectively No. 1 and No. 2. Each card is operated by a short lever-arm K2 marrying at its outer end a roller L'. P is a shaft on which are two cam-disks Pland P, the cam being formed by peripheral grooves which run partly on an upper level and partly on a ower level, the two levels being joined by a diagonal oove. In these grooves travel the rollers andlc as shown by dotted lines. Since the diagonal grooves in the two disks l?I and P are offset, the rollers k will pass their dia onals in succession, the traverse of a roller t rough its diagonal from one slot level to the other serving to swing the corresponding card throughvits entire range from open to closed position. Card No. 2, for instance, may be of high resistance and will be swung first from its open to closed position by cam P, as shown in Fig. 10, to remove its resistance from the circuit. Then card No. 1, which is of lower resistance and in series with card No. 2 in the same circuit, will be'swung by cam P1L to finally remove its resistance also from the circuit. The two cards will be operated in reverse order to bring them again into circuit. By such means any desired combinations of card movements may be reduced, using two cards or more. The sha t P may for instance be a controller shaft carrying a series-multiple switch for two railway motors and the two cams so shaped and related as to give the rheostatic conditions required in connection with such a switch. This'may be accomplished without resort to blow-out magnets and contactors such as are now emplo ed in such an organization.

n Figs. 11 and l12 one side of the loop is formed by a pile of carbon plates R, the other side by two ribbons A, A of low resistance. The carbon pile is so mounted in holders W1, W2 as to give one side of the pile the aforesaid curvature on a long-radius arc. In such a carbon pile it is feasible to vary itsI resista-nce through a certain range .by varying the pressure thereon, but beyond that ran e a heav pressure produces but slight re uction o resistance while iinally the compressed pile still remains in the circuit and adds its resistance thereto. By my device it becomes possible to finally remove from circuit the resistance of a compressed carbon pile, or the pile may be given a fixed degree of pressure and the entire variation range secured by using my device to progressively short circuit it. In Figs. 11 and 12 the compression of the carbon pile is effected by means of a cam S1, on a shaft worked by lever 0, acting on an angle-iever X, which at its upper end has an adjustable bearing block a: controlled by a screw y. A Second cam S2 on the same shaft acts in succession to cam S1 to swing the ribbons A, A and wrap them progressively around the curved face of the carbon pile. The ribbons are attached at one end to the metal plate r forming one terminal of the pile and at the other end to a tilting frame T, which is swung upward by cam S2 and drawn downward by a spring Z. After the carbon has been compressed by cam S1 to` a degree determined by adjusting screw y, the ribbons A, A will, by means of cam S, be wrapped progressively over the pile to short circuit it, coming iinally into contact with metal plate r1 forming the opposite terminal of the pile, as shown by dotted lines.

I have referred to the plating of the metallic resistance strip at non-variable points with copper to eliminate heating and perma nent resistance. This is also of value at those points of the conductor which lie against the support rods and thereby lose a part of their radiating surface.

It will be manifest that various other modifications and applications of the above described rheostat will be apparent to those skilled in the art.

What I claim as new and desire to secure by Letters Patent is:

1. A rheostat comprising a bare flexible conductor extended longitudinally between separated points of su port and a second conductor arranged to e pressed into contact therewith progressively.

2. A rheostat comprising two 'bare condoctors extended adJacent to each other in the same direction but at an an le to each other, one of them being flexible, and a presser acting thereon progressively.

3. A rheostat comprisin two hare conductors extended at an ang e to each other, and a presser acting thereon progressively to put tiem in electrical connection from end t0 en 4. A rheostat comprising a bare iexible conductor extended longltudinally under yielding tension between separated points of support, and a second extended conductor arranged to be ressed into contact therewith progressive y to vary the electrical resistance.

5. A rheostat comprising a bare flexible conductor of ribbon form extended longitudinaliy under yieding tension `between sepa.- rated points of support, and a Second extended conductr arranged to be pressed into contact therewith progressively to vary the resistance.

6. A rheostat comprising a bare conductor extended longitudinally, a. diver-ging bare conductor, and a. presser acting to bring the two conductors into contact progreively along a curved surface.

7. A rheostat comprisin a bare conductor of ribbon form extended mgitudinally under yielding tension, a normally diverging conductor, and a resser acting to bring the two conductors into contact progressively along a curved surface. y

8. A rheostat comprising a bare conductor extended longitudinall under yielding tension, a Second exten ed conductor and a. presser having a curved surface bearing on said conductors progressively to put them in contact progressively for varying their resistance.

9. A rheostat com rising a bare extended conductor, a secondJ divergently extended conductor, and a presser having a surface curved on a longer radius 'but oscillating on a shorter radius for putting said conductors into contact progressively.

10. A rheostat comprising a lbare. conductor extended in a. series of loops, and a presser for progressively bringing the two sides of the loop into electrical connection.

11. A rheostat comprising a bare flexible conductor extended in a lseries of loops and a. presser for progressively bringing the two sides of the loop into electrical connection.

12. A rheostat eomprisin a bare conductor of ribbon form extend face to face in a. series of loops and means for progressively connecting e ectrically the opposite sides of the loops.

13. A rheostat comprising a bare conductor extended in a series of oops and means for progressively brin 'ng into contact the opposite sides of the oops.

14. A rheostat comprising a bare conductor of ribbon form extended in a series of loops and means for bringing the opposite sides of the loops into contact progressively.

15 A rheostat comprisin a bare conductor of ribbon form exten ed in a iiexible loop having its two sides face to face and means for progressively Ibringing into contact the o posite sides of the loop.

16. A r eostat comprising a bare conductor extended in a loop and a presser bearing on the loop pro ively to connect electrically its opposlte sides.

17. A rheostat comprising an extended iexible conductor under tension but capable of yielding longitudinally, and a rockin presser bearing thereon to bring a secon extended conductor into contact therewith progressively.

18. A rheostat com rising a. presser, a conductor extending a ong said presser and presenting a curved surface, and a taut fiexile conductor arranged to bend progres' sively over said surface to vary the resistance.

19. A rheostat comprising a presser having a curved surface, and two conductors extending along said surface and brought into contact with each other progressively to va their resistance by bendingover said sur ace.

20. A rheostat comprising a bare resisting conductor extending along a rigid curved surface, and a second iexible conductor makin contact therewith progressively by ben ing over said surface.

21. A rheostat comprising a. presser having a curved surface, a flexible bare conductor extending under yielding tension and secured at one end to said presser and at its other end to a. stationary point, and a second conductor with which the {iexible conductor makes contact progressively by bending over said surface.

22. A rheostat comprising a presser having a curved surface, and a pair of iexible diverging conductors secured to one end of the presser and extended under yielding tension between said preer and a stationary point.

23. A rheostat compri a resser having a curved surface on eac si e and ilexible conductors extended oppositely from the opposite ends of said presser to stationary polnts.

24. A rheostat comprising a presser having a curved surface and a series of loo s of flexible conductor extending under yiel ing tension from one end of said presser to a stationary point and brought into contact progressively by bending over said curved surface.

25. A rheostat comprising a rocking presser with a curved surface and a. flexible bare conductor extended from one end of said presser to a stationery point and adapted to bend over the said curved surface as the presser is rocked to make contact progressively with a second conductor on said surface.

26. A rheostat com rising a presser of insulating material and two diverging bare conductors extended longitudinally and brought into contact progressively by said presser.

27. A rheostat comprising a bare conductor having dierent de rees of conductivity in different parts o its length and extended in a series of loops with a resser for progressively cutting out the reslstance of the conductor beginning at points of lesser conductivity.

28. A rheostat comprising a bare conductor ribbon of progressively increased cross section extending in a series of loops, and a presser for short circuiting the loops progressively beginning at points of smaller cross section.

29. A rheostat comprisin a tapering bare conductor ribbon extende in a series of loops having their two sides face to face and a presser for short circuiting the loops progressively beginning at the tapered end.

30. A rheostat comprising sets of bare conductor loops arranged to be short circuited progressively by means of a presser and an actuator for operating the several sets consecutively.

31. A rheostat comprising sets of bare conductor loops arranged to be short circuited progressively by means of a resser, the loops in the several sets being o different conductivity and an actuator for operating the said sets in succession.

32. A rheostat comprising a bare conductor extended in a series of loops ar- 1 ,massa ranged to be progressively short circuited by means of a presser, and having its conductivity reinforced at points not subjected to the presser action.

33. A rheostat comprising a bare conductor extended in a series of loops arranged to be progressively short circuited by means of a presser and having its conductlvity reinforeed by plating at points not subjected to the resser action.

34. n electrical resistance composed 0f a bare conductor extended between points of support in a series of loops and having its conductivity reinforced at those parts which are in contact with the supports.

35. An electrical resistance composed of a bare conductor extended between points of support in a series of loops and plated with conducting metal at those parts which are in contact with the supports.

36. A rheostat com rlsing a conductor of ribbon form extended) and offset at each loop to bring the sides of the loop into face-to-face relation and a presser for progressively short circuiting the loops by brlnging their opposite sides into contact.

Signed at New York city, county and State of N. Y., this 7th day of May, 1919.

EDWARD M. BENTLEY.

in a series of loops' 

